The present invention in particular relates to an adjustment device for a closure element on a vehicle.
Such closure element for example can comprise a window pane, a sunroof or a convertible top. Usually such closure elements nowadays are adjustable between a maximally open and a maximally closed position by external power via a drive motor of an adjustment device. For controlling the adjusting movement an electronic control unit is provided, which serves to control the rotational speed and the direction of rotation of a drive element of the drive motor coupled with the closure element. Such drive element, for example in the form of a drive shaft of the drive motor, then is coupled with the closure element via an adjustment mechanism of the adjustment device, in order to transmit an adjustment force to the closure element.
In particular in adjustment devices in the form of a vehicle window lifter it is known that an electronic control unit for controlling the drive motor comprises a bridge circuit, in order to supply the drive motor with electric power and control the rotational speed and the direction of rotation of the drive element. A typical bridge circuit here comprises four transistors, preferably four voltage-controlled field effect transistors.
In addition, further loads are provided on a vehicle, whose energization can be controlled via additional controllers and circuits separate from the adjusting movement of a closure element. One example of this is the window heater of a rear and/or side window of the vehicle or of a mirror. In practice, a control of the energization of a separate window heater for example is effected by means of at least one additional transistor.